textproduct: Albany

WHAT HAS CHANGED

Flood Watch for Flash Flooding expanded into the Capital Region, Lake George-Saratoga/Upper Hudson Valley region and Rensselaer County. Heavy rain and embedded thunderstorms will persist across the eastern Catskills north into these areas through daybreak, with a secondary area of moderate to heavy rain redeveloping for areas near and north of I-90 later this morning through early afternoon. QPF amounts have therefore increased in these areas with some amounts of 3-4" possible.

KEY MESSAGES

1) Multiple rounds of showers/thunderstorms will produce heavy rain through today, especially in the Flood Watch area. Poor drainage/urban areas will be most susceptible to potential flash flooding through today.

2) Despite areas of heavy rainfall, current river forecasts suggest threat for river flooding is low at this time. However, if any of the higher-end rainfall totals are realized then isolated minor river flooding would be possible.

DISCUSSION

KEY MESSAGE 1...

Multiple embedded mid level vortices have developed along the eastern periphery of developing upper level trough. Initial wave was located over the SE Catskills will continue tracking northward through daybreak, with moderate to heavy rain on its eastern side persisting across the NE Catskills into the upper Hudson Valley region. Rainfall rates up to 1-2"/hour will be possible, especially in favored upslope areas in the NE Catskills, and possibly NW Saratoga/western Warren Cos. Additional showers/thunderstorms with heavy rain will continue translating N/NE into the Taconics, NW CT/western MA and southern VT toward daybreak, with some rainfall rates potentially reaching up to 2"/hour.

As this initial wave rides north, another feature located off the NJ coast should lift toward LI and then southern New England later this morning and afternoon. This should allow an area of moderate to heavy rain across western New England to pivot westward, reaching areas near and north of I-90 including the Capital Region, the Lake George/Saratoga and upper Hudson Valley regions later this morning through mid afternoon. Rainfall rates could still reach 1-2"/hour within this area, which added to the prior rainfall, could increase chances for flash flooding, especially in poor drainage and urban areas. Therefore, the Flood Watch for Flash Flooding has been expanded northward into these areas.

Heavy rain should decrease in intensity toward and after sunset, with a general decrease in areal coverage of showers tonight.

KEY MESSAGE 2...

Latest HEFS (Ensemble River Forecasts) continue to show a low (generally <10-15%) chance for main stem river flooding with this event, likely due to antecedent dry conditions and rainfall deficits. However, rainfall amounts are siding on the higher end of forecasts, and latest NERFC forecasts do suggest the Hoosic River @ Williamstown could approach minor flood stage early this afternoon, with Esopus Creek @ Cold Brook also approaching minor FS early this morning. Will have to watch other points across the eastern Catskills and western New England through today given that higher rainfall totals are most likely going to be realized.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Light to moderate rain showers continue to move through all TAF sites through the TAF period. KPOU could still observe a thunderstorm through 7z, then observe light to moderate rain showers. Ceilings and visibilities continue to fluctuate through 29/18z between VFR/MVFR/IFR/LIFR conditions due to periods of moderate rainfall. For KGFL and KALB, forecast confidence is moderate on end timing of rain shower activity and a transition to patchy fog for later this afternoon into this evening. Winds continue to be less than 6 knots and variable through the TAF period.

Outlook...

Thursday Night: Low Operational Impact. Slight Chance of SHRA. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday Night: Moderate Operational Impact. Likely SHRA...TSRA. Monday: Moderate Operational Impact. Chance of SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...Flood Watch through this evening for CTZ001-013. NY...Flood Watch through this evening for NYZ041>043-048>054- 058>061-063>066-083-084. MA...Flood Watch through this evening for MAZ001-025. VT...Flood Watch through this evening for VTZ013>015.